The process of extracting shale oil and gas requires deep vertical drilling followed by horizontal drilling since the shale gas and oil are unconventional natural resources found at 2,500-5,000 m below the earth’s surface, as compared to conventional crude oil found at 1,500 m.
The most common way to extract shale gas is ‘hydraulic fracturing’ (fracking), where high volumes of water mixed with certain chemicals are pushed down to break the rocks and release the trapped energy minerals.
Fracking seems an attractive tool, both politically and economically. To gain such benefits, the government introduced a policy on shale gas and oil in 2013, permitting national oil companies to engage in fracking. Under the first phase, shale gas blocks were identified in Andhra Pradesh, Arunachal Pradesh, Assam, Gujarat, Rajasthan and Tamil Nadu. However, environmental groups have strongly criticised this move, which they say will have adverse environmental impacts.
Benefits of Fracking
- In the U.S., where shale gas has been commercially exploited for two decades, the prices of fuel and electricity have dropped.
- Recent negotiations between the Secretary of the Organisation of the Petroleum Exporting Countries (OPEC) and American shale producers to control oil production and prices show that the U.S. has gained significant political advantage.
- Similarly, if India commercially exploits shale deposits, it could meet its ever-increasing energy demand, decrease oil and gas imports, and improve the balance of payments.
Negative effects of Fracking
- Fracking consumes large amounts of water (average 15,000 m3/well) and relatively larger surface area, it is bound to impact irrigation and other local requirements.
- In the U.S. experience, out of 260 chemical substances, 58 have been identified to pose a risk to human life and environment, eight are carcinogens and 17 are toxic to freshwater organisms.
- As 25-90% of the fluid is not retrieved and cracks in the shaft are possible, there is a high risk of pollution to nearby underground water. Instances of groundwater pollution have been reported in the U.S. (Pennsylvania) and Canada.
- Fracking has other impacts such as increased air emissions (including greenhouse gases) and seismic activity. Environmental impact assessments of the European Union and the U.K. have recognised these risks. [The Hindu]